The present invention relates to a weight lifting machine and, more particularly, to a weight lifting machine which permits the user to select a sequence in which the weight is increase or decreased at various intervals during the workout routine or permits the user to adjust the weight during the workout routine without dismounting the machine.
Conventional weight lifting machines comprise a frame which includes a pair of spaced apart generally vertical tracks with a plurality of weights and a carriage movably mounted on the tracks. The carriage typically includes a select post or bar which extends through the central portions of the weights and is manually coupled to one or more of the weights to increase or decrease the weight coupled to the carriage. Typically, the weights are coupled to the select bar by a removable pin which extends through the weight and through a corresponding aperture in the select bar. The carriage also is connected to a cable on the distal end of which is connect a handle bar, with the cable being supported on the frame by a pair of pulleys. Therefore, when the user of the machine pulls on the handle bar the carriage moves up the tracks, with the resistance being a function of the number of weights that are coupled to the carriage. In order to vary the weight on the carriage, and therefore the resistance for the user of the machine, the user of the machine must return the carriage to the starting position and relocate the pin either to reduce the number of weights attached to the select bar or increase the number of weights attached to the select bar.
In some machines the adjustment requires the user to demount the machine. Furthermore, the adjustment requires a break in the routine and may prevent the user from reaching his or her optimal workout. As it is known in the weight lifting art, the key to obtaining maximum muscle building is to push the muscle beyond its normal everyday demands. Since muscle can recover some of its strength in a short duration, the user of the exercise machine may not achieve his or her maximum fatigue point when his or her exercise routine includes pauses when for example the user needs to change the weight.
More recently, exercise devices have incorporated variable resistance capabilities which allow the user of the exercise machine to maximize his or her benefits from the machine. For example, in U.S. Pat. No. 5,037,089 to Spagnuolo weights are selected by mechanical actuators which are controlled by the user of the exercise machine. The mechanical actuator includes a solenoid and a pin, which is held in place by a spring. When the solenoid is energized, the pin is withdrawn from the weight which reduces the resistance for the user of apparatus. The solenoids are controlled by a module which includes a microprocessor which permits the user of the equipment to increase or decrease the weight as desired. However, these actuators still rely on pins extending into and out of the selector bar. Therefore, the decoupling and coupling is not instantaneous. Moreover, there may be increased potential for jams, which result from misalignment of the pins with the select bar. Because these type of jams can not be manually fixed, there is an even greater potential for interruption.
Accordingly, there is a need for a weight lifting machine which allows the user of the machine to instantly vary the resistance during a workout and, further, to choose a preprogrammed workout, which does not include transition delays associated with the pin couplers.